Currently, refrigerated product storage and display cases which are used in supermarkets are typically provided with a door structure having a multi-paned window which is surrounded by a metallic door frame. To prevent condensation and frost from forming on the door frame, it is known in the art to provide electrical heating elements concealed within a groove at the outer edges of the door or within the door frame of the display case. The electric heater strips raise the surface dew point temperature so that condensate droplets do not form on the surface of the metal surfaces. Each time the door is opened, room ambient air or warmer, humid air tends to enter the refrigerated space, or when the door is closed, the door gasket may leak cold air which can cause the door frame and its jam to condense ambient condensate. The condensate can freeze to form frost or drip downwards onto the floor. The use of electric heater strips embedded in the door, primarily at the area of the door gasket seal has been utilized in order to reduce the formation of condensate. The electric heater strips either operate continually or are controlled by an enthalpy monitoring controller whereas they cycle based on the relative humidity relative to the ambient dry bulb temperature, i.e., dew point. Most supermarkets tend to leave these heaters on continuously in the summer because of the potential liability of having a wet floor in the shopping aisle. Having the heaters on also eliminates the frosted glass effect a high door opening rate has on moisture entering into the display case. The added cost of the door heater operation is rationalized by these factors. However, it is still desirable to provide a more efficient, less costly method of preventing condensate from forming on the door frame and the door jam.